1. Technical Field
The present method and apparatus relate to the attachment of a suture to a surgical needle.
2. Background of the Art
Surgical needles are well known in the art. A needle used in surgery is from 0.0025 to about 0.06 inches in diameter. Surgical needles are often curved. They typically have a butt, or "barrel" end with an axial hole drilled therein into which a suture is inserted for attachment after the suture is inserted. The needle is crimped or swaged to hold the suture in place. The swaging is performed so as to retain the suture in the needle such that a predetermined pull out force is required to separate the suture from the needle. Pull out forces are standardized and a list of standard pull out forces and suture diameters for a range of standard USP suture sizes is set forth in the U.S. Pharmacopeia. The sutures can be monofilament or multifilament. They can be bioabsorbable or non-bioabsorbable.
Generally, multifilament sutures are tipped prior to needle suture attachment. Multifilament sutures have a tendency to "broom" when cut. The tipping process adheres the filaments and facilitates insertion of the suture end into the hole in the needle.
Methods for attaching sutures to needles are known in the art and are disclosed and described in U.S. Pat. Nos. 5,046,350, 4,922,904, 4,799,311, 4,722,384, 4,072,041, 4,060,885, 4,054,144, and 3,910,282, for example.
However, significant problems occur when dealing with the attachment of microsurgical needles and sutures. Microsurgical needles are typically from about 0.0025 to about 0.0130 inches in diameter. Microsurgical sutures usually used range from about 0.0015 to about 0.0080 inches in diameter. Microsurgical needle-suture attachment procedures are typically assisted by the use of magnification optics such as magnifying lenses or video monitors connected to telescopic magnification optics. As can be expected it is difficult to manipulate sutures which can hardly be seen without magnification. To insert such sutures manually into the hole in the barrel end of a needle, even with magnification, is very time consuming. Yet, surprisingly, this is the method currently being employed. The apparatus now used includes a needle holder which is movable along a track to position the needle between the jaws of a swaging die. Video cameras with telescopic magnification lenses enable the operator to view the end of the needle. The operator holds the suture end between the fingers and slowly advances the suture end, trying to get it aligned with the needle end. It can take a skilled worker up to a minute to insert the suture into the needle and to secure it by swaging.
Clearly, it would be desirable to simplify and speed up the process of microsurgical needle-suture attachment. Accordingly, the apparatus and method described herein reduce the per needle insertion time to as little as 20 seconds. This corresponds to a 200% increase in efficiency with respect to the use of time.